1. Field of the Invention
The present invention relates to an ATM address mapping system in the OSI (open system interconnection) communication environment, and more particularly to an ATM dynamic address mapping system capable of dynamically mapping ATM addresses and NSAP addresses.
2. Description of the Related Art
Conventional means of dynamically mapping (address resolution) ATM addresses and network addresses (IP addresses) in the TCP/IP communication environment via an ATM-SVC network, is described in, for example, RFC1577.
The OSI communication environment through the ATM-SVC network, however, is not provided with means of dynamically mapping ATM addresses and network addresses (NSAP addresses).
Therefore, since only a statistic address resolution is possible in the OSI communication environment via the ATM-SVC network, an initialization work has been performed for previously defining a mapping table of ATM addresses and NSAP addresses in each end system or each relay system (router) within a network, prior to the system operation. The mapping table once set up in this way cannot be relieved until the end of the system operation.
As mentioned above, since it cannot help resolving addresses statistically in the conventional OSI communication environment via the ATM-SVC network, it has such a defect that an initialization work is required for previously defining a mapping table of ATM addresses and NSAP addresses in each end system or each relay system (router) within a network prior to the system operation.
Since the mapping table cannot be relieved until the end of the system operation, it has such a defect that the address information on an end system or a relay system of the other party having finished communication cannot be relieved also until the end of the system operation, thereby reducing memory use efficiency.
A first object of the present invention is to provide an ATM dynamic address mapping system and method capable of dynamically mapping ATM addresses and NSAP addresses (address resolution), in the OSI communication environment via the ATM-SVC network.
second object of the present invention is to provide an ATM dynamic address mapping system and method which can eliminate an initialization work for previously defining a mapping table of ATM addresses and NSAP addresses in each end system or each relay system (router) within a network, prior to the system operation.
A third object of the present invention is to provide an ATM dynamic address mapping system and method capable of relieving address information after finishing communication and therefore improving memory use efficiency, compared with the conventional method incapable of relieving address information on an end system or a relay system of the other party having finished communication until the end of the system operation.
According to the first aspect of the invention, a dynamic ATM address mapping system in an OSI communication environment via an ATM-SVC network, wherein
an ATM address server for registering and controlling address information of pair of ATM address and network address on each end system and relay system of a logical sub-network is provided within the logical sub-network,
each of the end system and relay system within the logical sub-network comprising
address information registration requesting means for requesting the ATM address server to register the address information of the own ATM address and network address in pair, and
address acquiring means for receiving an ATM address of a communication party from the ATM address server and registering the ATM address,
the ATM address server comprising
address registering means for registering the address information of the ATM address and network address in pair, upon receipt of the address information registration request from the end system and relay system, and
address notifying means for notifying an ATM address of a communication party required by the end system and relay system to the end system and relay system.
In the preferred construction, the ATM address server further comprises
an address correspondence table for registering the address information of each pair of ATM address and network address on each of the end system and relay system,
said address registering means of the ATM address server registering the address information of the ATM address and network address in pair into said address correspondence table, according to an address information registration request from an end system and relay system,
said address notifying means of the ATM address server receiving an ATM address of a communication party required by an end system and a relay system from said address correspondence table and notifying the ATM address, while
each of the end system and relay system within the logical sub-network further comprises
an address correspondence table for registering the ATM address of the communication party received from the ATM address server by said address acquiring means.
In another preferred construction, each of the end system and relay system further comprises
address information refresh means for deleting address entry on a corresponding end system or relay system of a communication party from said own address correspondence table, after finishing the communication with the end system of the communication party.
In another preferred construction, the ATM address server further comprises
address registration completion notifying means for sending a registration completion notice of the address information to the end system and relay system, while
the end system and relay system further comprises
address information registration completing means for receiving the registration completion notice of the address information from the ATM address server and recognizing the address information registration completion.
In another preferred construction, the end system and relay system further comprises
address information refresh means for deleting address entry on a corresponding end system or relay system of a communication party from said own address correspondence table, at a predetermined elapsed time without communication after finishing the communication with the end system of the communication party.
In another preferred construction, the end system and relay system further comprises
address query means for requesting the ATM address server to refer to an ATM address of a communication party, when receiving no ATM address information of the communication party, while
the ATM address server further comprises
address retrieval means for receiving the address query request from the end system and relay system and retrieving the corresponding ATM address from said own address correspondence table for a specified network address as a key
According to the second aspect of the invention, a dynamic ATM address mapping system in an communication environment via an ATM-SVC network, wherein
an ATM address server for registering address information of pair of ATM address and network address on each end system and relay system of a logical sub-network into an address correspondence table and controlling the address information, is provided within the logical sub-network,
the ATM address server comprising
address registering means for registering the address information of the ATM address and network address in pair into the own address correspondence table, according to a registration request of the address information of pair of the own ATM address and network address from the end system and relay system,
address retrieval means for retrieving the corresponding ATM address from said own address correspondence table for a specified network address as a key, according to the ATM address query request of a communication party from the end system and relay system, and
address notifying means for notifying the ATM address obtained as a result of the retrieval to the end system and relay system.
In the preferred construction, the ATM address server further comprises address registration completion notifying means for sending a registration completion notice of the address information to the end system and relay system.
According to the third aspect of the invention, a dynamic ATM address mapping method in an OSI communication environment via an ATM-SVC network, wherein
an ATM address server for registering address information of each pair of ATM address and network address on each end system and relay system of a logical sub-network into an address correspondence table and controlling the address information, is provided within the logical sub-network,
said method comprising the steps of:
in each of the end system and relay system within the logical sub-network,
requesting the ATM address server to register the address information of the own ATM address and network address in pair; and
receiving an ATM address of a communication party from the ATM address server and registering the ATM address into the address correspondence table; while
in the ATM address server,
registering the address information of the ATM address and network address in pair into the address correspondence table, upon receipt of the address information registration request from the end system and relay system; and
receiving an ATM address of a communication party required by the end system and relay system from the address correspondence table and notifying the ATM address to the end system and relay system.
In the preferred construction, a dynamic ATM address mapping method comprising the step of:
in the end system and relay system, deleting address entry on a corresponding end system or relay system of a communication party from the own address correspondence table, after finishing the communication with the end system of the communication party.
In another preferred construction, a dynamic ATM address mapping method comprising the step of:
in the ATM address server,
sending a registration completion notice of the address information to the end system and relay system; and
in the end system and relay system,
receiving the registration completion notice of the address information from the ATM address server and recognizing the address information registration completion.
In another preferred construction, a dynamic ATM address mapping method comprising the step of:
in the end system and relay system,
deleting address entry on a corresponding end system or relay system of a communication party from the own address correspondence table, at a predetermined elapsed time without communication after finishing the communication with the end system of the communication party.
In another preferred construction, a dynamic ATM address mapping method comprising the step of:
in the end system and relay system,
requesting the ATM address server to refer to an ATM address of a communication party, when receiving no ATM address information of the communication party; and
in the ATM address server,
receiving the address query request from the end system and relay system and retrieving a corresponding ATM address from the own address correspondence table for a specified network address as a key.
Other objects, features and advantages of the present invention will become clear from the detailed description given herebelow.